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Show Mr. Denos Page 2 November 7, 1997 would welcome the opportunity to meet with PRWUA to discuss any specific provisions of the DC/ JOA that PRWUA believes are inadequately addressed in PROSIM. The second general comment is a concern that demands to meet June Sucker flows were not included in PROSIM. PROSIM is capable of modeling a variety of demands on the river, including instream flow requirements ( IFRs) mandated by the Bonneville Unit M& I System EIS and CUPCA, or requests such as USF& W's. PROSIM can use whatever water is appropriate and available under the water rights, storage rights, and institutional arrangements and agreements to meet those demands. In the case of meeting instream flows, the model determines the water physically passing a node and credits such water toward the IFR. Any remaining deficit in meeting the simulated IFRs is presently set up to call on CUP storage in either reservoir or both to meet the desired flow. A flow request for the June Sucker could be modeled to call on storage if necessary to evaluate long- term impacts. The report was intended to document the development of the model, the calibration of the model, and the verification of the baseline scenario. Inclusion of the endangered species requests beyond the IFRs of the Bonneville Unit M& I System EIS was felt to be outside of the scope of the baseline scenario and report at the present time. The model has since been used to simulate additional scenarios, including several in the Wasatch County Water Efficiency Study and EIS and an in- house evaluation of USF& W instream flow requests, but it is beyond the scope of this report to summarize these scenarios. The District considers the endangered species issue to be a good example of the type of issue for which PROSIM is a useful tool. The third general comment concerns what PRWUA understands to be PROSIM's limitation to simulating only monthly averages. The model currently operates on a monthly timestep and is not set up to be a real- time operating model that would provide help in day- to- day operational decision making. We do not believe a model can replace the day- to- day judgements that water professionals now and in the future will make in managing the river. The model was developed as a planning tool having the ability to model varying operating scenarios over an extended period ( 40 years, currently the 1950 through 1989 hydrologic time series). The input data used in PROSIM are not monthly averages. Monthly values of flow, diversion, demand, inflow, precipitation, etc., are provided for each month of the 40- year simulation period, consisting of actual recorded monthly values where available or simulated values where actual data were unavailable. See section 2.3 on the hydrologic analysis for a description of how missing data were generated. ( For an in- depth description, see the PROSIM development document. Provo River Simulation Model Draft Technical Memorandum # 2 " Hydrological Analysis", dated January 1993). PROSIM does account for water right changes ( according to the Morse Decree) within a monthly timestep, but does not operate on a daily timestep. J:\ ENG\ CORT\ WPFlLES\ PROSIM\ PRWUARES. WPD File Code: 1. B. 15.062. C0.640 |